Lateral gaze angle estimation using relative eye separation

ABSTRACT

This invention provides for the automatic determination of a human&#39;s gaze angle. The gaze angle is assumed to be the same as the head angle (i.e., eyes looking straight ahead). It is determined by comparing the observed eye separation relative to a maximal eye separation. The gaze angle is then determined to be the inverse cosine, or arc cosine, of the ratio of these two measurements.

FIELD OF THE INVENTION

The present invention provides automatic lateral gaze angle estimationusing relative eye separation.

BACKGROUND OF THE INVENTION

There are many applications where detecting when a human user is lookingdirectly at a device is desirable. One such application is self-servicekiosks. The kiosk may be in a general attention attracting mode withflashy graphics until someone actually looks at the device. At thispoint, it may launch a targeted promotion because it has the user'sattention.

Kiosk application can be activated by simple proximity sensors or bymachine vision systems employing techniques such as backgroundsubtraction. However, these solutions only assure that a person isnearby, not that he is looking at the device.

Another application where detecting when a human user is lookingdirectly at a device is desirable is operator alertness monitoring. Atregular intervals, in order to operate the vehicle properly, theoperator of a machine may be required to look at various task-relevantareas or directions. For instance, an alert driver of a car needs tolook forward through the windshield and occasionally at the rearviewmirror. If this does not occur, or only one point is being looked at,the driver may have become drowsy. The proper alternation of direct gazebetween, e.g., the windshield and the rear-view mirror, may bedetermined by placing a gaze detector at each special point, e.g., thebase of the windshield and in the rearview mirror. One could also put asignaling device, such as a blinking light, in conjunction with thedetection camera to deliberately draw the user's attention to the spotif, for instance, the user is not looking in that direction frequentlyenough.

There are also a number of driver alertness systems. Many of these arebased on blink frequency or eyelid closing rate. As such, they do notensure that a driver is paying attention to the important aspects of hisenvironment (e.g., he may be facing the passenger or text messagingrather than looking straight ahead).

There are other applications where determining the gaze angle of a humansubject is important. Clearly, gaze angle of the user's head can be usedto infer what the user is looking at as, in general, the user is lookingin the direction of where his/her head is pointing. If the configurationof the user's external environment relative to the user is known,“interest” maps may be built if the user's gaze angle may be determined.For instance, as a customer roams down the aisle in a grocery store, amap of interest of the type of groceries that the user is interested inmay be built based upon which groceries the user looks at. For instance,if the user gazes towards pasta on one side of the aisle while ignoringanother ethnic food group on the other side of the aisle, it may bedetermined that the user has more interest in the pasta products.

There are some eye-tracking devices on the market. However, many ofthese eye-tracking devices must be worn by the user. Others are bulky orhave a limited range of acceptable positions for the user's head.

There are also many systems that may find human faces in video images,but they are typically limited to nearly frontal views and make noeffort to estimate head rotation or gaze direction. Systems thatadditionally determine head rotation often involve many templateconvolutions and hence are computationally costly.

Present methods for gaze angle such as a neural net classifier or adense stereo reconstruction that looks for the nose are computationallycomplex.

SUMMARY OF THE INVENTION

This invention estimates the gaze angle of the head of a human subjectusing one or more video cameras. Once determined, the gaze angle may beused to infer what the user is looking at in the user's environment ifthe configuration of the environment relative to the user is known.

This invention provides for the automatic estimation of a human's gazeangle. The gaze angle is assumed to be the same as the head angle (i.e.,eyes looking straight ahead). It is determined by comparing the observedeye separation relative to either a maximal eye separation, or theseparation measured from a different vantage point. There is generally aleft/right ambiguity to this result that can be resolved by simplyidentifying the side of the head the eyes are located.

One embodiment discloses a method for lateral gaze angle estimation of ahead of a user having two eyes using the determination of relative eyeseparation of the user, each eye having a pupil region, the methodcomprising finding the pupil region of each eye of the user in a videocamera image from a video camera, measuring an eye separation distancebetween the substantial centers of the pupil regions, and determiningthe lateral gaze angle based upon the measured distance.

Another embodiment illustrates a system for lateral gaze angleestimation of a head of a user using the determination of relative eyeseparation of the user, each eye having a pupil region, the systemcomprising at least one processing unit, a memory unit operablyassociated with the at least one processing unit, a lateral gazedetermination tool storable in the memory unit and executable by the atleast one memory unit, the lateral gaze determination tool comprising apupil region finding unit of each eye of the user in a video cameraimage from a video camera, an eye separation distance measuring unit formeasuring the separation distance between the substantial centers of thepupil regions, and a lateral gaze angle determining unit based upon themeasured distance.

In yet another embodiment, a computer program product is embodied in acomputer readable medium for operating in a system comprising aprocessing unit, a memory, a bus, and input/output (I/O) interfaces, forimplementing a method for estimating lateral gaze angle of a head of auser having two eyes using the determination of relative eye separation,each eye having a pupil region, the method comprising finding the pupilregion of each eye of the user in a video camera image from a videocamera, measuring an eye separation distance between the substantialcenters of the pupil regions, and determining the lateral gaze anglebased upon the measured distance.

Another embodiment discloses a method for deploying computinginfrastructure comprising integrating computer-readable code into acomputing system, wherein the code in combination with the computingsystem is capable of performing a process for lateral gaze angleestimation of a head of a user having two eyes using the determinationof relative eye separation of the user, each eye having a pupil region,the process comprising finding the pupil region of each eye of the userin a video camera image from a video camera, measuring an eye separationdistance between the substantial centers of the pupil regions, anddetermining the lateral gaze angle based upon the measured distance.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this invention will be more readilyunderstood from the following detailed description of the variousaspects of the invention taken in conjunction with the accompanyingdrawings in which:

FIG. 1 shows a data processing system suitable for implementing anembodiment of the present invention.

FIG. 2 shows a network for implementing an embodiment of the presentinvention.

FIG. 3 illustrates various examples of lateral gaze angles havingcorrespondingly different eye separation.

FIG. 4 illustrates one embodiment of a system of the present inventionhaving two cameras for identifying the gaze angle of a human ofinterest.

FIG. 5 illustrates an embodiment of the present invention having lenses,two rings of LEDs, and an optical axis.

FIG. 6 illustrates one embodiment of a method for scanning a user's eyesand pupil regions and for determining whether the user is looking at thevideo camera.

FIG. 7 illustrates one embodiment of the method of the present inventionfor determining the lateral gaze angle of a user's head based upon theobserved separation of the user's eyes with respect to the camera'sangle

FIG. 8 illustrates an embodiment of a lateral gaze estimation tool ofthe present invention.

The drawings are not necessarily to scale. The drawings are merelyschematic representations, not intended to portray specific parametersof the invention. The drawings are intended to depict only typicalembodiments of the invention, and therefore should not be considered aslimiting the scope of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides automatic lateral gaze angle estimationof a human of interest using relative eye separation.

The present invention may employ one or more standard video cameras, mayoperate in a non-contact mode, and may have a fairly wide working zone.Also, a complete image analysis is not required; only a method to findthe eyes of the human for which the invention is estimating a lateralgaze angle is required. Furthermore, resolving the gaze angle from twomeasurements is simple computationally.

A system, such as system 100, may have a data processing system, such asdata processing system 102 shown in FIG. 1, suitable for storing and/orexecuting program code of the present invention, and may include acomputer system, such as computer system 104, having at least oneprocessing unit (processing unit 106) coupled directly or indirectly tomemory elements (memory 110) through a system bus, such as system bus112. Memory 110 may include local memory (RAM 130) employed duringactual execution of the program code, bulk storage (storage 118), andcache memories (cache 132) that provide temporary storage of at leastsome program code in order to reduce the number of times code must beretrieved from storage 118 during execution. Input/output or I/O devices(such as display 120, and other external devices (external devices116)), including but not limited to keyboards, pointing devices, etc.,may be coupled to computer system 104 either directly or throughintervening I/O controllers (I/O interface(s) 114). I/O interface(s) 114may further couple video cameras 140,142 for finding a user's eyes tocomputer system 104. Network adapter(s) (network adapter 138) mayprovide access to external networks.

FIG. 2 illustrates a networked system, such as system 200, to enable adata processing system (data processing unit 202) to be coupled throughnetwork connection(s) (network connection 206, 208, 216, 218) to otherdata processing systems (data processing unit 204), remote printers(printer 212) and/or storage devices (storage 214) through interveningprivate and/or public network(s) (network 210).

The gaze angle of a human of interest is assumed to be the same as thehead angle (i.e., eyes looking straight ahead). It is determined bycomparing the observed eye separation relative to either a maximal eyeseparation, or the separation measured from a different vantage point.

For example, FIG. 3 illustrates three heads: right looking head 302,straight looking head 304, and left looking head 306. Each human head,of course, has two eyes 308 a, 308 b separated by distance d1, d2, d3.The gaze angle of the head with respect to a fixed location may make theappearance of the distance separating the user's eyes appear closertogether from the perspective of the fixed location. For instance,straight looking head 304, that is, looking directly at the point ofreference, has the maximal eye separation distance, d2, which is 10 inthe example shown in FIG. 3. That is, the eye separation distance forthe user cannot appear greater than d2 since the user's head is lookingstraight ahead at the point of reference. If the user's head is rightlooking (right looking head 302), that is, having a right lateral gazeangle, relative eye separation distance d1 will be less than the maximaleye separation distance, d2. In the example of FIG. 3, relative eyeseparation distance d1 is 8. If the user's head is left looking (leftlooking head 306), that is, having a left lateral gaze angle, eyeseparation distance d3 will be less than the maximal eye separationdistance, d2. In the example of FIG. 3, relative eye separation distanced3 is 6.

A video camera, such as video camera 140 and/or video camera 142,locates the human eyes and pupils (or pupil regions) of the human faceof interest and measures the distance between the eyes by counting thepixel distance between their centers in the image. Once the measurementhas been taken, the measurement is run through the formula of cos⁻¹(ratio of measurement and maximal value (10 in the example of FIG. 3)).The result is used by the system to estimate the lateral gaze angleestimation using relative eye separation. As shown in the calculationsof FIG. 3, straight looking head 304 has a lateral gaze angle of arccos(1.0), or 0 degrees. Right looking head 302 has a lateral gaze angle ofarccos (0.8), or +37 degrees. Left looking head 306 has a lateral gazeangle of arccos (0.6), or −53 degrees.

Another technique that can be used to determine lateral gaze is shown inFIG. 4 showing system 400 having camera 1 and camera 2. Camera 1 andcamera 2 each detect each eye and pupil or pupil region 410, 412 of ahead 402. Camera 1 acquires image 1 from its viewing angle. Thetechnique is to obtain the second image (image 2 by camera 2) at a knownangular offset relative to the view of camera 2. The eye separation inthe two views can then be compared to generate an estimate of the gazeangle. The separation of camera 1, camera 2 is known as is the relativeorientation of their optical axes (dotted lines). One way to solve thehead orientation position is to apply triangulation to determine theposition of each eye in space. This is possible because the imagecoordinates of the detected eye can be turned into a ray at a particularangle provided that the intrinsic parameters of the camera lens areknown. Using triangulation between the rays from the two cameras theactual position of each eye in space can be found. The angle of the lineconnecting the two eyes relative to the viewing direction of camera 1can then be computed directly. However, this method may be prone torange estimation errors that get magnified when determining the gazeangle.

Another technique for estimating lateral gaze angle is to compute theshift of view direction between the two cameras for the eye centers.This is the apex angle of the triangle formed by the center of the eyepair and the two cameras. Assuming the camera separation is B (base oftriangle) and the observed center angles are C1 and C2 (between the baseand the sides of the triangles). The relative viewing angle shiftA=180−C1−C2 (in degrees). The distances D1 and D2 from each camera tothe center point (legs of the triangle) can also be computed using B,C1, and C2. This can be combined with the eye separations S1 and S2observed in the two cameras to give the gaze angle relative to thecenter point. Let S2′=S2*D1/D2 to adjust for the magnification due todifferent distances. Equations S1=E*cos(G) and S2′=E*cos(G+A) where G isthe gaze angle relative to Camera 1 and E is the true separation of theeyes. Solving for E and substituting (i.e., the value of E does not needto known), constraint equation S2′*cos(G)=S1*cos(G+A) is arrived at.This can be solved for G=arctan [(S1*cos(A)−S2′)/(S1*sin(A))]. Comparingthe observed eye separations in this way is less sensitive to parallaxerrors than the direct stereo method.

Typically, the system first needs to find the pupil regions in the videoimage captured by video camera. A quick, simple, and reliable way to dothis is to utilize the “red-eye” effect. The red-eye effect is thecommon appearance of red pupils in color photographs of eyes. It occurswhen using a photographic flash very close to the camera lens, inambient low light. Because the light of the flash occurs too fast forthe pupil to close, much of the very bright light from the flash passesinto the eye through the pupil, reflects off the fundus at the back ofthe eyeball, and out through the pupil. The camera records thisreflected light. The red-eye effect is due to the color of the fundus,which is due to melanin, a pigment, principally located in the retinalpigment epithelium (RPE).

As shown in FIG. 5, a ring of near-infrared light-emitting diodes (LEDs508) are positioned around the camera lens and positioned near opticalaxis 506 of camera. LEDs 508 are flashed on and an image of theenvironment is acquired. (In optics, the term optical axis is used todefine a direction along which there is some degree of rotationalsymmetry. It can be used in several contexts. In an optical system, theoptical axis is an imaginary line that defines the path along whichlight propagates through the system. For a system composed of simplelenses (such as lenses 502, 504) and mirrors, the axis passes throughthe center of curvature of each surface, and coincides with the axis ofrotational symmetry. The optical axis is often coincident with thesystem's mechanical axis, but not always, as in the case of off-axisoptical systems.)

This is shown in method 600 in FIG. 6 which begins at 602 and continuesto 604. At 606, another image is then acquired with a similar ring ofLEDs (LEDs 510) further displaced from optical axis 506 of camera system140. (In optics, the term optical axis is used to define a directionalong which there is some degree of rotational symmetry. In an opticalsystem, the optical axis is an imaginary line that defines the pathalong which light propagates through the system.) This is shown as 506in FIG. 5 in system 500. For a system composed of simple lenses (lens502, lens 504) and mirrors, optical axis 506 passes through the centerof curvature of each surface, and coincides with the axis of rotationalsymmetry. The optical axis is often coincident with the system'smechanical axis, but not always, as in the case of off-axis opticalsystems.

At 608 of FIG. 6, possible retroreflectors are identified. (Aretroreflector (sometimes called a retroflector) is a device or surfacethat reflects light back to its source with a minimum scattering oflight. A human eye can be considered to be a retroreflector.) Next, at612, the system identifies pairs of detected regions that areapproximately the same shape and size and displaced horizontally in amanner indicative of a pair of eyes. At 614, the displacement betweenthe pupil pairs are measured.

Alternatively, the eyes might be found by template matching to a modeleye(s) or by looking for time differences in a video stream that areinduced by eye blink motions.

To resolve the left/right ambiguity it helps if the system can determinewhether the center of the eye pair is to the left or right of the centerof the head region (separately detected). However, if the intent is toonly recognize a direct gaze then this step is not needed—the user islooking directly at the camera when the eye separation is close to themaximum that has ever been observed (e.g., a separation within 2% of maxmeans gaze is ±11 degrees of direct).

One way of obtaining a maximal eye separation is to take the maximumobserved value over a time interval at 704 is shown in method 700 ofFIG. 7 which starts at 702. The currently observed separation is thencompared to this maximum value at 706 and the arc-cosine computed toderive the gaze angle at 708. This technique is effective if the user'shead stays at approximately the same distance (i.e., minimal loomingfrom perspective) and the user actively gazes from side to side(including straight forward at some point).

FIG. 8 illustrates a lateral gaze angle determination tool 800 for beingimplemented within memory 514 utilizing processing unit 512. Lateralgaze angle determination tool 800 has pupil finding component 802 thatperforms the function of finding the pupils of the human of interest.Tool 800 further has eye separation distance determining component 804for determining the distance between the eyes of the human of interestas found by pupil finding component 802. Eye separation distancedetermining component 804 has maximal eye separation distancedetermining unit 808 for determining an approximate maximal eyeseparation distance between the eyes of a “standard” human. Maximal eyeseparation distance determining unit 808 may be configured for recordingmultiple measured eye separation distances over a period of time anddetermining the maximal eye separation distance by identifying themaximum measured eye separation distance from the multiple measured eyeseparation distances. Lateral gaze angle determining component 806performs the function of determining the lateral gaze angle from theinformation received from eye separation distance determining component804. Lateral gaze angle determining component 806 has ratio calculatingunit 810 for calculating the ratio of the measured eye separationdistance to the maximal eye separation distance and calculating aninverse cosine value of the ratio. Lateral gaze angle determiningcomponent 806 may be configured to calculate the lateral gaze anglebased upon the calculated inverse cosine value.

It should be understood that the present invention is typicallycomputer-implemented via hardware and/or software. As such, and clientsystems and/or servers will include computerized components as known inthe art. Such components typically include (among others), a processingunit, a memory, a bus, input/output (I/O) interfaces, external devices,etc. It should also be understood that although a specific embodimentproviding lateral gaze angle estimation using relative eye separation ofa user has been depicted and described, the present invention could beimplemented in conjunction with any type of system where lateral gazeangle estimation is desirable.

While shown and described herein is a system and method for lateral gazeangle estimation using relative eye separation of a user, it isunderstood that the invention further provides various alternativeembodiments. For example, in one embodiment, the invention provides acomputer-readable/usable medium that includes computer program code toenable a computer infrastructure to provide lateral gaze angleestimation using relative eye separation of a user. To this extent, thecomputer-readable/useable medium includes program code that implementseach of the various process steps of the invention. It is understoodthat the terms computer-readable medium or computer useable mediumcomprises one or more of any type of physical embodiment of the programcode. In particular, the computer-readable/useable medium can compriseprogram code embodied on one or more portable storage articles ofmanufacture (e.g., a compact disc, a magnetic disk, a tape, etc.), onone or more data storage portions of a computing device, such as memoryand/or storage system (e.g., a fixed disk, a read-only memory, a randomaccess memory, a cache memory, etc.), and/or as a data signal (e.g., apropagated signal) traveling over a network (e.g., during awired/wireless electronic distribution of the program code).

In another embodiment, the invention provides a computer-implementedmethod for lateral gaze angle estimation using relative eye separationof a user. In this case, a computerized infrastructure can be providedand one or more systems for performing the process steps of theinvention can be obtained (e.g., created, purchased, used, modified,etc.) and deployed to the computerized infrastructure. To this extent,the deployment of a system can comprise one or more of (1) installingprogram code on a computing device, such as computer system from acomputer-readable medium; (2) adding one or more computing devices tothe computer infrastructure; and (3) incorporating and/or modifying oneor more existing systems of the computer infrastructure to enable thecomputerized infrastructure to perform the process steps of theinvention.

As used herein, it is understood that the terms “program code” and“computer program code” are synonymous and mean any expression, in anylanguage, code or notation, of a set of instructions intended to cause acomputing device having an information processing capability to performa particular function either directly or after either or both of thefollowing: (a) conversion to another language, code or notation; and/or(b) reproduction in a different material form. To this extent, programcode can be embodied as one or more of: an application/software program,component software/a library of functions, an operating system, a basicI/O system/driver for a particular computing and/or I/O device, and thelike.

The one or more program modules discussed herein carry out themethodologies disclosed herein. Flowcharts may illustrate architecture,functionality, and operation of possible implementations of systems,methods and computer program products according to various embodimentsof the present invention. In this regard, each block in the flowchartmay represent a module, segment, or portion of code, which comprises oneor more executable instructions for implementing the specified logicalfunction(s). It should also be noted that, in some alternativeimplementations, the functions noted in the blocks may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently. It will also benoted that each block of flowchart illustration can be implemented byspecial purpose hardware-based systems that perform the specifiedfunctions or acts, or combinations of special purpose hardware andcomputer instructions.

The foregoing description of various aspects of the invention has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed, and obviously, many modifications and variations arepossible. Such modifications and variations that may be apparent to aperson skilled in the art are intended to be included within the scopeof the invention as defined by the accompanying claims.

1. A method for lateral gaze angle estimation of a head of a user havingtwo eyes using the determination of relative eye separation of the user,each eye having a pupil region, each pupil region having a substantialcenter, the method comprising: finding the pupil region of each eye ofthe user from a video camera; measuring an eye separation distancebetween the substantial centers of the pupil regions; and estimating thelateral gaze angle based upon the measured distance.
 2. The method asdefined in claim 1 further comprising determining a maximal eyeseparation distance.
 3. The method as defined in claim 2 furthercomprising calculating a ratio of the measured eye separation distanceto the maximal eye separation distance and calculating an inverse cosinevalue of the ratio and determining the lateral gaze angle based upon thecalculated inverse cosine value.
 4. The method as defined in claim 3further comprising lighting up the pupil regions of the eyes of the userwith infrared light using a first and a second set of infrared lightemitting diodes, receiving and processing reflections of the infraredlight from the eyes of the user.
 5. The method as defined in claim 2further comprising recording multiple measured eye separation distancesover a period of time and determining the maximal eye separationdistance by identifying the maximum measured eye separation distancefrom the multiple measured eye separation distances.
 6. The method asdefined in claim 1 finding the pupil of each eye of the user with asecond camera, measuring a second eye separation distance between thesubstantial centers of the pupil regions from the second camera, anddetermining the lateral gaze angle based upon a comparison of themeasured eye separation distance and the second measured eye separationdistance.
 7. A system for lateral gaze angle estimation of a head of auser having two eyes using the determination of relative eye separationof the user, each eye having a pupil region, the system comprising: atleast one video camera; at least one processing unit; a memory unitoperably associated with the at least one processing unit; a lateralgaze determination tool storable in the memory unit and executable bythe at least one memory unit, the lateral gaze determination toolcomprising: a pupil region finding unit of each eye of the user in avideo camera image from a video camera; an eye separation distancemeasuring unit for measuring the separation distance between thesubstantial centers of the pupil regions; and a lateral gaze angledetermining unit based upon the measured distance.
 8. The system asdefined in claim 7 wherein the eye separation distance measuring unitcomprises a maximal eye separation distance determining unit.
 9. Thesystem as defined in claim 8 wherein the lateral gaze angle determiningunit comprises a ratio calculating unit for calculating the ratio of themeasured eye separation distance to the maximal eye separation distanceand calculating an inverse cosine value of the ratio.
 10. The system asdefined in claim 9 wherein the lateral gaze angle determining unit isconfigured to calculate the lateral gaze angle based upon the calculatedinverse cosine value.
 11. The system as defined in claim 8 wherein themaximal eye separation distance determining unit is configured forrecording multiple measured eye separation distances over a period oftime and determining the maximal eye separation distance by identifyingthe maximum measured eye separation distance from the multiple measuredeye separation distances.
 12. The system as defined in claim 7 furthercomprising a second camera for finding the pupil of each eye of the userwith a second camera, the eye separation distance measuring unitmeasuring a second eye separation distance between the substantialcenters of the pupil regions from the second camera, and the lateralgaze angle determining unit determining the lateral gaze angle basedupon a comparison of the measured eye separation distance and the secondmeasured eye separation distance.
 13. A computer program productembodied in a computer readable medium for operating in a systemcomprising a processing unit, a memory, a bus, and input/output (I/O)interfaces, for implementing a method for estimating lateral gaze angleof a head of a user having two eyes using the determination of relativeeye separation, each eye having a pupil region, the method comprising:finding the pupil region of each eye of the user in a video camera imagefrom a video camera; measuring an eye separation distance between thesubstantial centers of the pupil regions; and determining the lateralgaze angle based upon the measured distance.
 14. The computer programproduct as defined in claim 13 wherein the method further comprisesdetermining a maximal eye separation distance.
 15. The computer programproduct as defined in claim 14 wherein the method further comprisescalculating a ratio of the measured eye separation distance to themaximal eye separation distance and calculating an inverse cosine valueof the ratio.
 16. The computer program product as defined in claim 15wherein the method further comprises determining the lateral gaze anglebased upon the calculated inverse cosine value.
 17. The computer programproduct as defined in claim 16 wherein the method further comprisesrecording multiple measured eye separation distances over a period oftime and determining the maximal eye separation distance by identifyingthe maximum measured eye separation distance from the multiple measuredeye separation distances.
 18. A method for deploying computinginfrastructure comprising integrating computer-readable code into acomputing system, wherein the code in combination with the computingsystem is capable of performing a process for lateral gaze angleestimation of a head of a user having two eyes using the determinationof relative eye separation of the user, each eye having a pupil region,the process comprising: finding the pupil region of each eye of the userin a video camera image from a video camera; measuring an eye separationdistance between the substantial centers of the pupil regions; anddetermining the lateral gaze angle based upon the measured distance. 19.The method for deploying computing infrastructure comprising integratingcomputer-readable code into a computing system as defined in claim 16wherein the process further comprises determining a maximal eyeseparation distance comprising recording multiple measured eyeseparation distances over a period of time and determining the maximaleye separation distance by identifying the maximum measured eyeseparation distance from the multiple measured eye separation distances.20. The method for deploying computing infrastructure comprisingintegrating computer-readable code into a computing system as defined inclaim 19 wherein the process further comprises calculating a ratio ofthe measured eye separation distance to the maximal eye separationdistance and calculating an inverse cosine value of the ratio andfurther comprising determining the lateral gaze angle based upon thecalculated inverse cosine value.